[PATCH v4 26/32] gpu: nova-core: vgpu: negotiate the GSP plugin RPC version

[Alok Kumar <alkumar@nvidia.com>]

From: Zhi Wang <zhiw@nvidia.com>

The host must negotiate the RPC protocol with the booted GSP plugin
before sending instance configuration.

After observing the plugin's ready marker, initialize the shared RPC
buffers and submit the existing typed version-negotiation request
through the instance's PluginRpc channel.

Co-developed-by: Eliot Courtney <ecourtney@nvidia.com>
Signed-off-by: Eliot Courtney <ecourtney@nvidia.com>
Signed-off-by: Zhi Wang <zhiw@nvidia.com>
Signed-off-by: Alok Kumar <alkumar@nvidia.com>
---
 drivers/gpu/nova-core/vgpu/commands.rs       | 12 +++++++++++-
 drivers/gpu/nova-core/vgpu/fw.rs             |  4 ++--
 drivers/gpu/nova-core/vgpu/fw/commands.rs    |  1 -
 drivers/gpu/nova-core/vgpu/gsp_plugin_rpc.rs |  2 --
 drivers/gpu/nova-core/vgpu/instance.rs       |  3 +++
 5 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/nova-core/vgpu/commands.rs b/drivers/gpu/nova-core/vgpu/commands.rs
index 00da8fa4f910..a68841fe4019 100644
--- a/drivers/gpu/nova-core/vgpu/commands.rs
+++ b/drivers/gpu/nova-core/vgpu/commands.rs
@@ -28,13 +28,15 @@
         commands::{
             VgpuPropertiesSchema, //
         },
+        RpcMessage, //
         GMCAPI_CMD_BOOTLOAD_GSP_VGPU_PLUGIN_TASK,
         GMCAPI_CMD_CLEANUP_GSP_VGPU_PLUGIN_RESOURCES,
         GMCAPI_CMD_QUERY_ASSIGNED_VF_VGPU_TYPE,
         GMCAPI_CMD_QUERY_VGPU_PROPERTIES,
         GMCAPI_CMD_SHUTDOWN_GSP_VGPU_PLUGIN_TASK,
-        GMCAPI_CMD_SHUTDOWN_GSP_VGPU_PLUGIN_TASK_COMPLETE, //
+        GMCAPI_CMD_SHUTDOWN_GSP_VGPU_PLUGIN_TASK_COMPLETE,
     },
+    gsp_plugin_rpc::PluginRpc,
     instance::Gfid, //
 };
 
@@ -160,3 +162,11 @@ pub(super) fn send_cleanup(
     dev_dbg!(dev, "cleanup: gfid={} done\n", gfid.get());
     Ok(())
 }
+
+/// Negotiate the host protocol with a bootloaded GSP plugin.
+pub(super) fn negotiate_plugin_version(
+    dev: &device::Device<device::Bound>,
+    rpc: &mut PluginRpc<'_, '_>,
+) -> Result {
+    rpc.rpc_call(dev, RpcMessage::VersionNegotiation, &[])
+}
diff --git a/drivers/gpu/nova-core/vgpu/fw.rs b/drivers/gpu/nova-core/vgpu/fw.rs
index d80f36465296..6cec92c9b505 100644
--- a/drivers/gpu/nova-core/vgpu/fw.rs
+++ b/drivers/gpu/nova-core/vgpu/fw.rs
@@ -10,8 +10,6 @@
 
 use crate::gsp::bindings;
 
-pub(super) use commands::RpcMessage;
-
 pub(super) use bindings::{
     GSP_PLUGIN_BOOTLOADED,
     VGPU_CPU_GSP_COMMUNICATION_BUFF_TOTAL_SIZE,
@@ -29,6 +27,8 @@
     VGPU_CPU_GSP_VGPU_TASK_LOG_BUFF_REGION_SIZE, //
 };
 
+pub(super) use commands::RpcMessage;
+
 pub(super) const GMCAPI_CMD_QUERY_ASSIGNED_VF_VGPU_TYPE: u32 =
     bindings::GMCAPI_COMMANDS_GMCAPI_CMD_QUERY_ASSIGNED_VF_VGPU_TYPE;
 
diff --git a/drivers/gpu/nova-core/vgpu/fw/commands.rs b/drivers/gpu/nova-core/vgpu/fw/commands.rs
index 917de4d21861..c3d0acece2eb 100644
--- a/drivers/gpu/nova-core/vgpu/fw/commands.rs
+++ b/drivers/gpu/nova-core/vgpu/fw/commands.rs
@@ -30,7 +30,6 @@
 use super::bindings;
 
 /// Message types supported by the nova-core plugin RPC channel.
-#[expect(dead_code)]
 #[derive(Clone, Copy)]
 #[repr(u32)]
 pub(crate) enum RpcMessage {
diff --git a/drivers/gpu/nova-core/vgpu/gsp_plugin_rpc.rs b/drivers/gpu/nova-core/vgpu/gsp_plugin_rpc.rs
index 0ee32f011f63..696127c7169f 100644
--- a/drivers/gpu/nova-core/vgpu/gsp_plugin_rpc.rs
+++ b/drivers/gpu/nova-core/vgpu/gsp_plugin_rpc.rs
@@ -65,7 +65,6 @@ pub(super) fn comm(&self) -> &CommBufferRegion<'map, 'gpu> {
     }
 
     /// Initialize the control and response buffers for the first RPC.
-    #[expect(dead_code)]
     pub(super) fn init_rpc(&mut self) -> Result {
         self.comm.initialize()?;
         self.message_sequence = 0;
@@ -82,7 +81,6 @@ fn next_sequence(&self) -> u32 {
     }
 
     /// Write one RPC message, ring the VF doorbell, and wait for its response.
-    #[expect(dead_code)]
     pub(super) fn rpc_call(
         &mut self,
         dev: &device::Device<device::Bound>,
diff --git a/drivers/gpu/nova-core/vgpu/instance.rs b/drivers/gpu/nova-core/vgpu/instance.rs
index 8a2d8e3970a3..445d7f513fdc 100644
--- a/drivers/gpu/nova-core/vgpu/instance.rs
+++ b/drivers/gpu/nova-core/vgpu/instance.rs
@@ -31,6 +31,7 @@
 
 use super::{
     commands::{
+        negotiate_plugin_version,
         send_bootload,
         send_cleanup,
         send_shutdown,
@@ -156,6 +157,8 @@ impl<'gpu> VgpuInstance<'gpu> {
     fn activate(&mut self, vgpu: &VgpuManager<'gpu>) -> Result {
         let dev = vgpu.dev;
         self.bootload(dev, vgpu.cmdq, &vgpu.fifo_engine_list)?;
+        self.plugin_rpc.init_rpc()?;
+        negotiate_plugin_version(dev, &mut self.plugin_rpc)?;
 
         Ok(())
     }
-- 
2.53.0